The present invention relates to a defect inspection method applied to a device or the like which optically inspects defects, extraneous materials, or the like of a fine pattern formed on a sample through a thin film process typified by a semiconductor manufacturing process or a flat panel display manufacturing process and a device using the defect inspection method.
As a related art in the field of the invention, JP 2012-21994 A (Patent Document 1) discloses a technique of irradiating a sample with linearly-formed illumination light and simultaneously detecting scattered light generated from the sample with three-directionally-arranged detectors, and processing signals output from the detectors to detect the defects on the sample. In addition, JP 5-137047 A (Patent Document 2) discloses a focus detection method and a focus detection device using a specific pattern or a specific object image for the purpose of easily sensing a focus position of an optical system. In addition, JP 2006-47308 A (Patent Document 3) discloses an optical system including a plurality of detection systems simultaneously detecting reflected light or scattered light from an illuminated position.